Zipperless wetsuits have an advantage over zipper entry wetsuits in that they provide greater flexibility. Zippers by design are relatively rigid components of a wetsuit and, while they can flex to some extent, they can not stretch or contract at all along their length. Thus, when a surfer, for example, bends over or crouches down, a zipper entry wetsuit does not stretch in the back region along the spine, which either limits the surfer's ability to crouch down or causes the wetsuit to tighten in the neck and crotch regions. When a surfer arches his back, the zipper region does not contract, which can result in the neck region riding up the back side of the surfer's neck. Wetsuit designers tend to compromise by providing a zipper that is slightly shorter or longer than ideal.
One of the design challenges in eliminating the zipper from a wetsuit is to provide the neck region with sufficient expansion capability to allow a person to get into and out of the wetsuit, yet also allow the neck opening to be resealed snugly around the neck.
Japanese publication Utility Model Hei 7-6097, published Jan. 27, 1995, entitled "wet suit," discloses a zipperless wetsuit having a V-shaped cut in the neck and front region with a triangular fan shaped gusset sewn into the cut. An elongated, wrap-around strap is attached at the upper end of the cut, and mechanical fasteners secure the strap around the neck. While provision of a sewn-in gusset may improve the waterproof ability of the wetsuit, the gusset has the effect of restricting the extent to which the neck opening can be expanded for entry and may add an undesirable amount of bulk in the neck region.
U.S. Pat. Nos. 4,809,364 of Lent and 4,907,295 of Yasuda disclose zipperless wetsuits and are mentioned for background purposes.